An airplane airfoil generally consists of a frame and a skin. The frame may comprise a plurality of spars, ribs (optional) and stringers (optional). The frame and the skin of the airfoil form a box structure. Since the frame comprises large quantities of spars, ribs and stringers, the structure of the frame is complex.
During the manufacture of such components having a box structure for an airplane airfoil (e.g. a wing, a flap, an aileron, a slat, an empennage or the constitution parts thereof), the connection of the skin and the spars is complex and time-consuming. In the prior art, the connection of the skin and the spars is generally achieved by means of bonding or fasteners (such as rivets).
If the connection is achieved by means of bonding, firstly, it will be necessary to position the skin and the spars; then a plurality of clamps are installed to tightly clamp the positioned skin and spars, so as to guarantee no relative displacement occurs during the connection of the skin and the spars. However, due to the large quantities of the spars, large quantities of the clamps are needed for installation, which makes the installation process very time-consuming.
If the connection is achieved by means of rivets, the positioning between the skin, which has a curved shape, and the spars is difficult though no large quantities of the clamps are needed. Moreover, when the skin covers on the frame to form a closed box structure, it is necessary for the installation personnel to enter inside of the closed box structure to prosecute the riveting operation, which further makes the manufacture difficult.
Especially in the components having a box structure which has a small inner space (such as a flap trailing edge), in the case that honeycomb fills are filled or ribs are arranged therein, the connection of the skin and the spars are even more harder due to the small inner space of the components having a box structure.